<!DOCTYPE html>
<html>
<head>
	<title>随机链接</title>
</head>
<body>

</body>
<script type="text/javascript">
	var rd = Math.random();
	if(rd>0.5){
		document.write("<a href='..'>学习web</a>");
	} else {
		document.write("<a href='../../../www.baidu.com'>度娘</a>");
	}
</script>
</html>